Incidental catch and estimated discards of pelagic sharks from the swordfish and tuna fisheries in the Mediterranean Sea
Large pelagic sharks are caught incidentally in the swordfish and tuna fisheries of the Mediterranean Sea. In our study, twelve shark species were documented as bycatchover three years from 1998 to 2000. Blue shark (Prionace glauca) was the predominant species in all gears and areas examined. Shortfin mako (Isurus oxyrinchus), common threshershark (Alopias vulpinus), and tope shark (Galeorhinus galeus) were the next most abundant shark species—found in more than half of the areas sampled. Catch composition varied both in the areas and gears investigated. Sharks represented 34.3% in weight of total catches sampled in theAlboran Sea and 0.9% in the Straits of Sicily. Higher shark catches were observed in the swordfish longline fishery, where a nominal CPUE value reached 3.8 sharks/1000 hooks in the Alboran Sea. Size distribution by fishing gear varied significantly. Albacore longline catches consisted mainlyof juveniles, whereas subadult and adult specimens were more frequent in the swordfish longline and driftnetfishery. The percentage of sharks brought onboard alive was exceptionally high; only 5.1% of the specimens died. Few discards (seven blue shark) were recorded in the Greek longline fleet during onboard sampling in the Aegean Se
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Format: | article biblioteca |
Language: | English |
Published: |
2005
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Subjects: | Biology, Ecology, Fisheries, |
Online Access: | http://hdl.handle.net/1834/25631 |
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Summary: | Large pelagic sharks are caught incidentally in the swordfish and tuna fisheries of the Mediterranean Sea. In our study, twelve shark species were documented as bycatchover three years from 1998 to 2000. Blue shark (Prionace glauca) was the predominant species in all gears and areas examined. Shortfin mako (Isurus oxyrinchus), common threshershark (Alopias vulpinus), and tope shark (Galeorhinus galeus) were the next most abundant shark species—found in more than half of the areas sampled. Catch composition varied both in the areas and gears investigated. Sharks represented 34.3% in weight of total catches sampled in theAlboran Sea and 0.9% in the Straits of Sicily. Higher shark catches were observed in the swordfish longline fishery, where a nominal CPUE value reached 3.8 sharks/1000 hooks in the Alboran Sea. Size distribution by fishing gear varied significantly. Albacore longline catches consisted mainlyof juveniles, whereas subadult and adult specimens were more frequent in the swordfish longline and driftnetfishery. The percentage of sharks brought onboard alive was exceptionally high; only 5.1% of the specimens died. Few discards (seven blue shark) were recorded in the Greek longline fleet during onboard sampling in the Aegean Se |
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